Need help Renhdering Static Mesh Material to Texture (Beginner)

Hi everyone,

I am a Unity developer without experience in Unreal Engine. Recently I have purchased an asset (a weapons pack) from the Marketplace and I am planning to use it in my Unity-based game. I have previously been able to complete this process once, by exporting FBX and textures as separate files and working with them in Unity. This asset is giving me issues as textures on weapons aren’t the regular Albedo/Metallic/NM, but are some weird Section/Shade/NM textures hooked up to a custom material.
I have found this Render To Texture Blueprint Toolset | Unreal Engine Documentation and I presume this will help export the usable textures as BC/Metallic/NM from a screenshot. Since I have no experience in Unreal Engine, this process is very confusing. I was able to follow the instructions here Render to Texture Toolset Setup | Unreal Engine Documentation, but currently I’m stuck here: Render an Unwrapped Static Mesh Material to Textures | Unreal Engine Documentation. I have made a static mesh from the previous skeletal mesh that is the weapon, but I am unsure what to do with the materials. the manual says:
“The mesh should have a material with the companion material function “UnwrapUVsforRender” hooked up to the WorldPositionOffset input. There must also be a few parameters hooked up to the material function. A scalar parameter named “Size” should be hooked up to the Size input; a vector parameter named “RenderLocation” must be hooked up to render location, and a scalar parameter named “Unwrap” should be hooked up to the Unwrap input.”
I don’t understand how these instructions should be applied on the existing material.
What is the “companion material function” and how is it related to ‘material attributes’ that previous parameters end in?
How do I specify the World position offset?
“There must also be a few parameters hooked up to the material function.” Which material function?
“A scalar parameter named “Size” should be hooked up to the Size input…” UnwrapUVsforRender does not have a size input.
I tried running the command ke * rendertextures without these changes to materials, but nothing happens. No message, no new files/folders, nothing.

If somebody could lead me through this it would be greatly appreciated. I’m sure it’s something simple, I just don’t understand these workflows. Thanks in advance!